I think the "cancel-rebook" explanation is a red herring. Yes, it might have been a factor, but that's easily fixed by having a cancellation fee. Reservations being totally non-refundable at any date or time are an entirely different matter and it's a power grab.

Also, I tried booking directly with the hotel networks several times recently, in most cases non-refundable was all they offered, or the option of refundable was so much more expensive that it bordered on ridiculous.